Subtitled Worlds of Science Fiction when it started, the Worlds of part came and went during the Fifties, often being placed on the cover in a manner that allowed one to misread the full title as Worlds of If. Robert Guinn seems to have been a bit uncertain of the exact title after he bought it in 1959. The title is given in a variety of ways in the indicia, annual statements of ownership, etc.; it is worth noting, however, that Guinn never thought it was Worlds of If. Universal seems to have also been confused about the magazines title for a while; they finally settled on Worlds of If in 1972 and we have listed the subsequent issues under that title.